This invention relates to a culture apparatus for cultivating (or incubating) cultures such as cells, microbes and the like in a cultivating chamber.
A culture apparatus, which has been conventionally called an incubator, cultivates cultures (samples) such as cells, microbes and the like as culture targets in an aseptic cultivating chamber while keeping temperature of the cultivating chamber and gas concentration of carbon dioxide (CO2), Oxygen (O2) or the like constant. As shown in FIG. 4, a culture apparatus 100 includes an insulating box body 102 comprising an outer metal box 110 having an opening 102A at one side thereof and an inner stainless box 116 provided inside the outer box 110. In addition, a cultivating chamber 104 is formed in a space (inner box 116) surrounded by a door (inner door 118) blocking the opening 102A in a free-opening/closing manner. The cultivating chamber 104 is vertically partitioned by a plurality of shelves 106 on which vessels 108 that contain cultures are placed.
The culture apparatus 100 is provided with an air circulation fan 128 for controlling circumferences in the cultivating chamber 104, which is arranged in a duct 124, and a gas concentration measuring device 130 having a gas concentration measuring sensor for carbon dioxide or oxygen (not shown). The gas concentration measuring device 130 communicates to the cultivating chamber 104 via pipes 134 and 136 for guiding gas in the cultivating chamber 104 to the gas concentration measuring sensor. An ultraviolet lamp 150, which is arranged within the cultivating chamber 104, irradiates the cultivating chamber 104 with an ultraviolet ray to sterilize circulating air, and gas is gathered from a measuring hole 138 stopped by a rubber stopper 140 for the purpose of measuring gas concentration in the cultivating chamber 104.
The insulating box body 102 is provided with an outer door 114 for blocking the opening 102A in a free-opening/closing manner, and the cultures are sent in and drawn out of the cultivating chamber 104 by opening/closing of the outer door 114 and the inner door 118. An insulating material 112 for heat conservation is provided inside the outer box 110, and a circulation path 120 of air or water is formed between the inner box 116 and the outer box 110. A heater 122 is arranged in the circulation path 120. Heat generated from the heater 122 is transferred to the cultivating chamber 104 by thermal conduction to the inner box 116 and heat transfer from the circulation path 120 by air or water to keep the cultivating chamber 104 at a temperature appropriate for cultivation. This allows the cultures, such as cells, microbes and the like, to be cultivated in the cultivating chamber 104 (see Japanese Patent Application Publication No. 2005-118021).
Such a culture apparatus 100 should be used while keeping the cultivating chamber 104 clean at all times. However, if cultivated cells or microbes are infected with bacteria, virus or the like, the cultivating chamber 104 and air in the cultivating chamber 104 of the culture apparatus are contaminated. Thus, in order to keep the cultivating chamber 104 clean, the cultivating chamber 104 is swept clean or is sterilized by being heated at a high temperature of more than 90° C. with a heater (not shown).
As described above, in the prior art, in order to keep the cultivating chamber clean, the cultivating chamber 104 has to be swept clean or be sterilized by being heated at a high temperature of more than 90° C. with a heater. However, this technique could not thoroughly sterilize the culture apparatus including the gas concentration measuring sensor, the pipes connected to the gas concentration measuring device and every corner of the cultivating chamber.
In addition, heat-resistant germs are incompletely sterilize even at the high temperature of more than 90° C., and further, about 8 hours are required to restart the cultivation through a cooling process from the increase of temperature of the cultivating chamber for sterilization by heating. This may lead to a problem of too much time during which the culture apparatus can not be used for cultivation.